Field of the Disclosure
The disclosure relates to blood treatment systems and methods. More particularly, the disclosure relates to systems and methods for combining an adsorption device and a blood separation system.
Description of Related Art
Various blood processing systems now make it possible to collect particular blood constituents, rather than whole blood, from donors or patients. Typically, in such systems, whole blood is drawn from a donor, the particular blood component or constituent is removed and collected, and the remaining blood constituents are returned to the donor. By thus removing only particular constituents, potentially less time is needed for the donor's body to return to pre-donation levels, and donations can be made at more frequent intervals than when whole blood is collected. This increases the overall supply of blood constituents, such as plasma and platelets, made available for health care.
Whole blood is typically separated into its constituents through centrifugation. This requires that the whole blood be passed through a centrifuge after it is withdrawn from, and before it is returned to, the donor. To avoid contamination and possible infection of the donor, the blood is preferably contained within a sealed, sterile fluid flow system during the entire centrifugation process. Typical blood processing systems thus include a permanent, reusable centrifuge assembly containing the hardware (drive system, pumps, valve actuators, programmable controller, and the like) that spins and pumps the blood, and a disposable, sealed and sterile fluid processing assembly that is mounted in cooperation on the hardware. The centrifuge assembly engages and spins a disposable centrifuge chamber in the fluid processing assembly during a blood separation step. The blood, however, makes actual contact only with the fluid processing assembly, which assembly is used only once and then discarded.
As the whole blood is spun by the centrifuge, the heavier (greater specific gravity) components, such as red blood cells, move radially outwardly away from the center of rotation toward the outer or “high-G” wall of a separation chamber included as part of the fluid processing assembly. The lighter (lower specific gravity) components, such as plasma, migrate toward the inner or “low-G” wall of the separation chamber. Various ones of these components can be selectively removed from the whole blood by forming appropriately located channeling seals and outlet ports in the separation chamber of the fluid processing assembly. For example, one application of therapeutic plasma exchange involves separating plasma from cellular blood components, collecting the plasma, and returning the cellular blood components and a replacement fluid to the donor.
After the blood has been separated into its constituent parts, it may be desirable to further process one more of the separated components. For example, in an alternative version of a therapeutic plasma exchange procedure, rather than replacing a patient's plasma with a different fluid, the patient's own plasma may be treated and returned after separation. This may be most efficiently achieved by pairing the blood separation system with a secondary processing device, such as an adsorption device or column. The adsorption device will remove undesirable substances from the plasma by immuno-adsorption. The exact substances removed depend upon the needs of the patient. For example, the substances removed from the plasma by the adsorption device may include low-density lipoproteins and Lipoprotein (a) for patients suffering from severe hypercholesterolemia. In another example, pathogenic antibodies may be removed from the plasma, for patients suffering from autoimmune diseases and organ transplant rejection, or as a pre-treatment before transplantation. In yet another example, fibrinogen, fibrin, and/or C-reactive protein may be removed from the plasma, for treating microcirculation disorders and ischemic tissue damage. Exemplary adsorption devices include the TheraSorb® line of products from Miltenyi Biotec GmbH Corporation of Bergisch Gladbach, Germany. Other examples of adsorption devices suitable for removing undesirable substances from plasma are described in greater detail in U.S. Pat. No. 6,569,112 to Strahilevitz, which is incorporated herein by reference.
One disadvantage of known systems which combine a blood separation system with an adsorption device is the amount of manual intervention and oversight required. Typically, an operator must monitor the adsorption device to ensure that a suitable amount of plasma is entering the adsorption device, so as to not overload the device. If the operator does not properly monitor the adsorption device, plasma will not be properly processed and may be returned to the patient without having the undesirable substances removed therefrom. Furthermore, when using “active” adsorption columns the operator must actively monitor any reservoir bags to ensure that large amounts of blood components are not removed from the patient without proper component replacement, as decreased effective circulating volume (“ECV”) can severely compromise a patient's health. Accordingly, the need remains for blood treatment systems and methods which combine the separation and further processing functions while eliminating or at least reducing the amount of manual intervention and oversight required.